Audio interface/garageband level prob?

[Jack of Alderaan]

Oye oye you good people of the internet, hear my plea and please save me from miseryyyyyy:

I bought an old M Audio Fast Track usb interface to go with an old mac laptop my father gave me. I decided to test it with some basic recording....

I used an SM57 as a drum mono OH, through a small mackie mixing desk into the m audio interface (i also tried a RB500 through a pre73jr preamp then into the mackie or straight into the audio interface, but problem is the same). I also use GarageBand. So what' s the problem? On the mackie the signal peaks towards 0 dBu so i should be alright, but on the audio interface there's a red light telling me it's almost clipping. Isnt that strange? Even stranger, on GarageBand the coloured VU goes fully into yellow/orange on each snare beat but the red light never appears, so GarageBand is telling me it's not clipping. And however hard i hit it never clips. It is as though the audio interface is acting as a limiter, at least the soundwave looks like it! Is such thing possible? It seems i need to have a really low signal on the mackie not to make the interface go red. For the signal/noise ratio, not pretty good! Well, i dont know if that makes any sense but i just dont understand whats going on.

I have a second question regarding GarageBand and signal level. My very stubborn father told me that just as long as it's not clipping then it's alright, even if GarageBand non-numerical VU peaks at yellow and orange. I was pretty confident signal should be in the green aera, with a few yellow on the louder beats. Who is right? Who is wrong? Shoud you kill the father or blame the son! ;-)

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[CrowsofFritz]

I have this happen all the time. On my ART preamps, the signal goes way into the red, but it’s a healthy signal in the DAW. I’m not really curious about it, so I’ve never questioned it. As long as it’s fine in the DAW, I don’t really mind.

 

[ecc83]

I do not have Garage Band but in ANY DAW you should be recording at 24 bits and so the average level should be around -20dBFS on the meters. Peaks should never hit much more than -8dBFS and neg six only only very rare, very loud peaks. Recording even lower, -30dB e.g. will still give you a decent dynamic range as you can always boost digitally post tracking with no noise penalty.

If you are forced to record at 16 bits that is a bit of a restraint but you can still average around -15dBFS, just need to watch those peaks.

Dave.

 

[Jack of Alderaan]

I do record in 24 bits. Problem is looking at the VU of the mixing desk (or some valve preamp i borrowed) i hardly reach 0 dBu of ouput. But the interface's LED is already in red, even when its input is turn really low, almost to 0...shouldnt i have lots of headroom at disposal before it reaches 0 dBFS and starts clipping?

To make the interface not clipping/limiting i have to reach no more than -20 dBu in analog. Even that and it's still walking on a tight rope.

 

[JamEZmusic]

Yeah, your pre-amp is outputting a Line level signal, you can go into your interface mic pre-amps with minimum pre-amp gain and you will be coming in pretty hot most likely, if you're not clipping you're fine.

If I am running through an external pre-amp with 1 mic then I will go into a DI box (as hot as I can because I like what it does) and from that into the interface mic inputs with the PAD engaged. if using 2 mics and because I only have 1 DI box, I don't bother using that but instead go to the interface LINE IN on minimum gain with the PAD engaged. I never clip when doing this but I do come in hotter that I'd like.

I'll tweak the level on the interface to get roughly -10dbfs or -12dbfs PEAKS.

If your interface has a line in, I would use that. If no line in then you just need to use the mic pre-amps on minimum gain, if you still end up clipping occasionally, or it's affecting your performance by trying to hold yourself back, turn the volume down a touch on the guitar, or get a DI box.

The RB500 mic you have. is that the Tbone RB500 ribbon? If so. I love mine, it's almost a secret weapon for harsh sources. How did you come about using that mic?

edit: those VU meters are so misleading anyway. not all VU meters show the output, maybe you're seeing the input reading which can be way below nominal but your master output is far hotter? And again, they miss faster transients so your VU meter will show very different to your interface meter. I was given an audio developments field recorder the other day and I was messing with that. I don't understand those VU meters at all, there is no 0db mark, it just goes from like 1 to 7. I took a wild guess and picked 4 to hover around and I calibrated to that using test tone which happens to hit -18dbfs exactly in DAW but in reality I am pinning the meter hard into (clipping) or so you would think but the source still sounds fairly clean. I'm very new to that device and don't really know too much about it yet. But it's confusing as hell.

Oh also, some interfaces do have an on board limiter, I have on mine although never used it, I don't even think I have it activated?.
I think it's way more likely your mackie mixer is compressing the signal though. Again, going back to that field recorder I was pushing the signal way more aggressive that I ever would for real (this is how I learn) and the waveform looked pretty brickwalled (and sounded too saturated) to me even though I was coming into my interface at great levels without any need for boosts.

crowsoffrits: if you are reading this, I have a couple of ArtPreV3's, how do you find them? I feel like I am not using mine in the best way, I have experimented with it a fair bit but there are so many choices to choose from. As it stands at the moment, it's just a Bass Guitar Mic Pre, because from what I gather, this is what they excel at, even when comparing to some of the real high end pre-amps. Did you try it out on acoustic or nylon guitar yet?

Those ARTPres VU meters show either the input stage, or the output stage depending on if you are in OPL mode I think. Even so..... as simple as the pre-amp seems, it's quite complex IMO, too many choices!, if I push into a little distortion and look at the waveform, it's only the top half of the waveform that gets squashed while the bottom looks like it has retained all of it's dynamics? Ever notice this?

 

[CrowsofFritz]

Yeah, your pre-amp is outputting a Line level signal, you can go into your interface mic pre-amps with minimum pre-amp gain and you will be coming in pretty hot most likely, if you're not clipping you're fine.

If I am running through an external pre-amp with 1 mic then I will go into a DI box (as hot as I can because I like what it does) and from that into the interface mic inputs with the PAD engaged. if using 2 mics and because I only have 1 DI box, I don't bother using that but instead go to the interface LINE IN on minimum gain with the PAD engaged. I never clip when doing this but I do come in hotter that I'd like.

I'll tweak the level on the interface to get roughly -10dbfs or -12dbfs PEAKS.

If your interface has a line in, I would use that. If no line in then you just need to use the mic pre-amps on minimum gain, if you still end up clipping occasionally, or it's affecting your performance by trying to hold yourself back, turn the volume down a touch on the guitar, or get a DI box.

The RB500 mic you have. is that the Tbone RB500 ribbon? If so. I love mine, it's almost a secret weapon for harsh sources. How did you come about using that mic?

edit: those VU meters are so misleading anyway. not all VU meters show the output, maybe you're seeing the input reading which can be way below nominal but your master output is far hotter? And again, they miss faster transients so your VU meter will show very different to your interface meter. I was given an audio developments field recorder the other day and I was messing with that. I don't understand those VU meters at all, there is no 0db mark, it just goes from like 1 to 7. I took a wild guess and picked 4 to hover around and I calibrated to that using test tone which happens to hit -18dbfs exactly in DAW but in reality I am pinning the meter hard into (clipping) or so you would think but the source still sounds fairly clean. I'm very new to that device and don't really know too much about it yet. But it's confusing as hell.

Oh also, some interfaces do have an on board limiter, I have on mine although never used it, I don't even think I have it activated?.
I think it's way more likely your mackie mixer is compressing the signal though. Again, going back to that field recorder I was pushing the signal way more aggressive that I ever would for real (this is how I learn) and the waveform looked pretty brickwalled (and sounded too saturated) to me even though I was coming into my interface at great levels without any need for boosts.

crowsoffrits: if you are reading this, I have a couple of ArtPreV3's, how do you find them? I feel like I am not using mine in the best way, I have experimented with it a fair bit but there are so many choices to choose from. As it stands at the moment, it's just a Bass Guitar Mic Pre, because from what I gather, this is what they excel at, even when comparing to some of the real high end pre-amps. Did you try it out on acoustic or nylon guitar yet?

Those ARTPres VU meters show either the input stage, or the output stage depending on if you are in OPL mode I think. Even so..... as simple as the pre-amp seems, it's quite complex IMO, too many choices!, if I push into a little distortion and look at the waveform, it's only the top half of the waveform that gets squashed while the bottom looks like it has retained all of it's dynamics? Ever notice this?

Yeah, I actually learned the VU meters dont show headroom at all. I dont think the ARTPre is all that great. AFAIK, it IS a starved plate design whereas the MPA II has a high voltage setting to make use of those tubes.

Yeah, my classical guitar with a Neumann into the MPA II is choice. Sounds fantastic.

 

[JamEZmusic]

Ah Nice one!

I was thinking of buying the MPAII as it happens. If this Audio Developments field recorder does the job, I may not need to. I might have gotten lucky, the Pre-amps are the same as the ones used in Neve consoles, Much more experimentation needed before I can really make up my mind though.

Cheers for the reply!